Typical antiperspirant compositions for use in atomizing aerosols are based on astringent active salts suspended in silicone, silicone oil, or organic oil. In order to achieve satisfactory atomization thereof, comparatively large volumes of propellant, dilutant and/or solvent, in relation to the antiperspirant are necessary, both for providing sufficient pressure for the atomization process and for reducing the viscosity of the antiperspirant suspension. The propellant is conventionally a liquefiable propellant, such as short-chain aliphatic hydrocarbons (e.g., propane or butane) or short-chain ethers (e.g., dimethyl ether).
An effect of such typical antiperspirant compositions together with the propellant used therein is a spray which feels cold on the skin due to the low boiling point of the propellant and the effect of its rapid evaporation. The cooling has a less comfortable feeling upon the skin compared with liquids which evaporate less rapidly or have a higher boiling point. Another effect of such typical antiperspirant compositions is dryness and irritation/stinging of the skin. There is also a tendency for a white residue to be left on the skin, which can leave unwanted white marks on dark clothing.
An alternative to these typical antiperspirant compositions are water-based compositions, in which astringent salts are dissolved in an aqueous solution. Such water-based compositions may be water-in-oil emulsions. For example, WO 01/24766, WO 96/24326 and U.S. Pat. No. 4,695,451 disclosed particular water-in-oil emulsions for use as antiperspirant compositions. Such water-based compositions may also be single-phase compositions. For example, WO 96/18378 disclosed a single-phase antiperspirant composition having an astringent active salt dissolved in a polyol, wherein water was used as a polyol-solubilizing agent.